Which means, if you don't implement it until then, users would probably have to wait for this feature at least six more months (until Ubuntu 14.10).

On the other hand, I am not even sure Sylpheed 3.4.0 final can make it into Ubuntu 14.04 LTS, as Ubuntu 14.04 LTS already reached the Debian Import Freeze and both Debian and Ubuntu do not even have Sylpheed 3.4.0beta8 in their repositories yet: